Frozen out: The campaign aims to highlight threats to the Arctic and to ban drilling for oil and unsustainable fishing in its waters

Greenpeace said the Arctic belonged to the whole world because it was defined in international law as the high seas.

But the Arctic states, Russia, Canada, the US, Norway and Denmark are making territorial claims on the seabed to allow in oil companies, the environmental campaigners warned.

The campaign to protect the Arctic, which was launched at the Rio+20 global conference on sustainable development in Rio de Janeiro, Brazil, is backed by dozens of famous names from TV, film, music and sport.

Their names are being written on an 'Arctic scroll', a petition which Greenpeace hopes to get signed by one million people. It will then be planted on the seabed, 2.5 miles (4km) below the ice and marked by a 'flag for the future'.

Which way is North? The bear-suited campaigner appears to ask a policeman for directions in front of Big Ben

Move along now: The realistic puppet meets a policewoman and a passer-by in just one of many identical stunts taking place across the world

Sir Paul said: 'The Arctic is one of the most beautiful and last untouched regions on our planet, but now it's under threat.

'Some countries and companies want to open it up to oil drilling and industrial fishing and do to the Arctic what they've done to the rest of our fragile planet.

'It seems madness that we are willing to go to the ends of the Earth to find the last drops of oil when our best scientific minds are telling us we need to get off fossil fuels to give our children a future.

'At some time, in some place, we need to take a stand. I believe that time is now and that place is the Arctic.'

Greenpeace International executive director Kumi Naidoo said: 'The Arctic is coming under assault and needs people from around the world to stand up and demand action to protect it.

Day trip: The polar bear made a real splash after a hard day's work on unfamiliar territory

'A ban on offshore oil drilling and unsustainable fishing would be a huge victory against the forces ranged against this precious region and the four million people who live there.

'And a sanctuary in the uninhabited area around the pole would in a stroke stop the polluters colonising the top of the world without infringing on the rights of Indigenous communities.'

Greenpeace is concerned that drilling in the Arctic could damage the region's fragile ecosystem and access more fossil fuels which are already driving the world towards dangerous climate change.

Native people have also warned their traditional way of life and survival are under threat from large scale oil exploration developments, with global oil companies beginning to drill at offshore sites in the Arctic.